Stoke Finishes EMPEROR Enrollment and Sets 2027 NDA Path

The Tip Desk · August 4, 2026 · 4 min read

The RNA-medicine company closed enrollment of 162 patients in June and said cash of $420.0 million is expected to fund operations through a potential U.S. launch of zorevunersen in early 2028.

Stoke Therapeutics (STOK) completed enrollment of 162 patients in the U.S., U.K. and Japan in June, finishing the planned primary analysis population for its Phase 3 EMPEROR study of zorevunersen in Dravet syndrome.

The RNA medicine company said a Phase 3 readout is anticipated in the third quarter of 2027. Those data are expected to complete a rolling U.S. New Drug Application submission in the second half of 2027. Stoke expects a pre-NDA meeting with the FDA in the second half of 2026 and to initiate the rolling NDA process in the first quarter of 2027.

That schedule is tighter than the company’s January update, which had pointed to a mid-2027 readout and a rolling NDA start in the first half of 2027. First-quarter commentary had still framed enrollment of about 150 patients as expected to finish in June. The June close of 162 patients put the pivotal study on the later-half 2027 completion path.

As of July 31, approximately 145 patients were through Week 8 and had received either two 70 mg loading doses of zorevunersen or sham. About 80 were through Week 24, with one dose remaining in the 52-week treatment period. About 60 had reached Week 28, the time point at which the primary endpoint of change in major motor seizure frequency will be measured. The first patients are expected to reach Week 52 in August 2026. No patients have discontinued treatment in the study.

An additional cohort of about 30 patients is being enrolled in Germany, France, Spain and Italy, where sham is administered via needle prick. Screening for that cohort has closed, and the last patient is expected to be enrolled in August 2026. Site activation and screening are also underway in China, where zorevunersen was recently granted Breakthrough Therapy Designation. Enrollment there is anticipated to complete in the second half of 2026. Data from the Europe and China cohorts are not planned for inclusion in the U.S. NDA.

Chief Executive Officer Ian F. Smith said the company has confidence in zorevunersen’s potential, citing no treatment discontinuations in EMPEROR and supportive four-year safety and efficacy data from ongoing open-label extension studies.

Beyond Dravet, dose escalation continues in the Phase 1 OSPREY study of STK-002 in autosomal dominant optic atrophy. All eight planned sites are active in the U.K., Germany, Denmark, Italy and Austria. Dosing of the first cohort of three patients is complete, with no serious or severe safety events reported to date. Dosing of the second cohort is expected to begin in August 2026. Subject to ongoing safety assessments, third and fourth cohorts are expected to follow, with a readout of safety and efficacy results anticipated in the first half of 2027. Lead optimization is underway for a clinical candidate in SYNGAP1-related disorders, and early research is expanding to new haploinsufficient targets, primarily in the central nervous system. Thomas McCauley joined as Chief Scientific Officer in July.

Revenue recognized for the three months ended June 30, 2026, was $9.3 million, down from $13.8 million a year earlier. Revenue comes from collaboration and licensing agreements with Acadia and Biogen. Net loss was $61.6 million, or $0.93 a share, compared with a net loss of $23.5 million, or $0.40 a share, in the year-ago quarter. The quarter included $10.8 million of non-cash stock-based compensation.

Research and development expenses were $49.5 million, up from $25.9 million a year earlier. The increase was driven by higher activity and personnel expenses to support the advancement of zorevunersen. Selling, general and administrative expenses were $25.3 million, up from $15.3 million, due to growth in personnel and launch readiness expenses.

Cash, cash equivalents and marketable securities were $354.3 million as of June 30, 2026. After that date, Stoke generated $65.7 million in net proceeds from an ATM sale to a single investor, bringing the total to $420.0 million. Those funds are expected to support operations through potential U.S. commercialization of zorevunersen in early 2028.